The present invention relates to novel azapeptide compounds, compositions comprising such compounds and methods of using them for the treatment of Hepatitis C Viral infections.
Infection by hepatitis C virus (xe2x80x9cHCVxe2x80x9d) is a compelling human medical problem. HCV is recognized as the causative agent for most cases of non-A, non-B hepatitis. Four million individuals may be infected in the United States alone.
WO 99/07734 assigned to Boehringer Ingelheim discloses azapeptides which inhibit NS3 protease useful in treating Hepatitis C. WO 99/20272 assigned to Merck and Co., discloses azapeptides useful as cell adhesion inhibitors. U.S. Pat. No. 5,837,687 and U.S. Pat. No. 5,965,538 both assigned to Fujirebro, disclose bicyclic ring azapeptides. WO 99/40063 assigned to Yoshitomi, discloses azapeptides having hydroxamic acid derivatives.
The HCV genome encodes a polyprotein of 3010-3033 amino acids [Choo, Q. -L., et al. xe2x80x9cGenetic Organization and Diversity of the Hepatitis C Virus,xe2x80x9d Proc. Natl. Acad. Sci. USA, 88, pp. 2451-2455 (1991); Kato, N. et al., xe2x80x9cMolecular Cloning of the Human Hepatitis C Virus Genome From Japanese Patients with Non-A, Non-B Hepatitis,xe2x80x9d Proc. Natl. Acad. Sci. USA, 87, pp. 9524-9528 (1990); Takamizawa, A. et al., xe2x80x9cStructure and Organization of the Hepatitis C Virus Genome Isolated From Human Carriers,xe2x80x9d J. Virol., 65, pp. 1105-1113 (1991)]. The HCV nonstructural (NS) proteins are presumed to provide the essential catalytic machinery for viral replication. The NS proteins are derived by proteolytic cleavage of the polyprotein [Bartenschlager, R. et al., xe2x80x9cNonstructural Protein 3 of the Hepatitis C Virus Encodes a Serine-Type Proteinase Required for Cleavage at the NS3/4 and NS4/5 Junctions,xe2x80x9d J. Virol., 67, pp. 3835-3844 (1993); Grakoui, A. et al. xe2x80x9cCharacterization of the Hepatitis C Virus-Encoded Serine Proteinase: Determination of Proteinase-Dependent Polyprotein Cleavage Sitesxe2x80x9d, J. Virol., 67, pp. 2832-2843 (1993); Grakoui, A. et al., xe2x80x9cExpression and Identification of Hepatitis C Virus Polyprotein Cleavage Products,xe2x80x9d 1385-1395 (1993); Tomei, L. et al., xe2x80x9cNS3 is a Serine Protease Required for Processing of Hepatitis C Virus Polyprotein,xe2x80x9d J. Virol., 67, pp. 4017-4026 (1993)].
The HCV NS protein 3 (NS3) contains a serine protease activity that helps process the majority of the viral enzymes, and is thus considered essential for viral replication and infectivity. The first 181 amino acids of NS3 (residues 1027-1207 of the viral prolyprotein) have been shown to contain the serine protease domain of NS3 that processes all four downstream sites of the HCV polyprotein [C. Lin et al., xe2x80x9cHepatitis C Virus NS3 Serine Proteinase: Trans-Cleavage Requirements and Processing Kinetics,xe2x80x9d J. Virol., 68, pp. 8147-8157 (1994)].
The HCV NS3 serine protease and its associated cofactor, NS4A, helps process all of the viral enzymes, and is thus considered essential for viral replication. This processing appears to be analogous to that carried out by the human immunodeficiency virus aspartyl protease, which is also involved in viral polyprotein processing. HIV protease inhibitors, which inhibit viral protein processing, are potent antiviral agents in man, indicating that interrupting this stage of the viral life cycle results in therapeutically active agents. Consequently the HCV NS3 serine protease is an attractive target for drug discovery.
There is a need for new treatments and therapies for HCV infection. It is, therefore, an object of this invention to provide compounds useful in the treatment or prevention or amelioration of one or more symptoms of HCV infection.
It is a further object herein to provide methods of treatment or prevention of HCV.
A still further object of the present invention is to provide methods for modulating the activity of serine proteases, particularly the HCV NS3/NS4a serine protease, using the compounds provided herein.
The present invention relates to azapeptide compounds represented by the formula: 
wherein:
(a) n 3-7;
(b) R1=a substituted or unsubstituted amino acid or analog thereof;
(c) R2=substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl;
substituted or unsubstituted arylalkyl;
substituted or unsubstituted alkoxycarbonyl, or
substituted or unsubstituted aryloxycarbonyl;
(d) R3=xe2x80x94Oxe2x80x94CH(R4)xe2x80x94R5; Oxe2x80x94R5, or Sxe2x80x94R5,
wherein R4 is selected from the group consisting of:
H;
halo;
cyano;
substituted or unsubstituted alkyl, and
substituted or unsubstituted alkenyl;
and wherein R5 is selected from the group consisting of:
substituted or unsubstituted alkyl;
substituted or unsubstituted haloalkyl;
substituted or unsubstituted haloalkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl, and
substituted or unsubstituted arylalkyl,
or a pharmaceutically acceptable salt thereof.
The present invention further relates to a method of treating Hepatitis C comprising administering an effective amount of a compound having the formula: 
wherein:
(a) n=3-7;
(b) R1=a substituted or unsubstituted amino acid or analog thereof;
(c) R2=substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl;
substituted or unsubstituted arylalkyl;
substituted or unsubstituted alkoxycarbonyl or
substituted or unsubstituted aryloxycarbonyl;
(d) R3=xe2x80x94Oxe2x80x94CH(R4)xe2x80x94R5, xe2x80x94Oxe2x80x94R5, or xe2x80x94Sxe2x80x94R5,
wherein R4 is selected from the group consisting of:
H;
halo;
cyano;
substituted or unsubstituted alkyl, and
substituted or unsubstituted alkenyl;
and wherein R5 is selected from the group consisting of
substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted haloalkyl;
substituted or unsubstituted haloalkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl, and
substituted or unsubstituted arylalkyl,
or a pharmaceutically acceptable salt thereof.
The following definitions and terms are used herein:
The term xe2x80x9camino acidxe2x80x9d, as used herein, refers to organic compounds having the structure: 
Amino acids useful in the present invention include, but are not limited to Alanine (Ala), Arginine (Arg), Asparagine (Asn), Aspartic Acid (Asp), Cysteine (Cys), Glutamic Acid (Glu), Glutamine (Gln), Glycine (Gly), Histidine (His), Isoleucine (Ile), Leucine (Leu), Lysine (Lys), Methionine (Met), Phenylalanine (Phe), Proline (Pro), Serine (Ser), Threonine (Thr), Tryptophan (Trp), Tyrosine (Tyr), Valine (Val). Said amino acids can be substituted or unsubstituted. The amino acids can be in the D or L configuration in the present invention.
Amino acid analogs useful in the present invention include, but are not limited to, substituted proline, pipecolic acid, cyclohexylglycine, tert-butylglycine, D-xcex3-carboxyglutamic acid (D-Gla), and aminoadipic acid.
The term xe2x80x9cpeptide bondxe2x80x9d, as used herein, means the linkage that is formed between individual amino acids that is formed by the elimination of a molecule of water from the amino group of one amino acid and the carboxyl group of the next amino acid.
The term xe2x80x9cheteroatom,xe2x80x9d as used herein, means a nitrogen, sulfur, or oxygen atom. Groups containing one or more heteroatoms may contain different heteroatoms.
The term xe2x80x9calkylxe2x80x9d, as used herein, means an unsubstituted or substituted, straight or branched, saturated hydrocarbon chain. Said hydrocarbon chain having 1 to 8 carbon atoms, and preferably, unless otherwise stated, from 1 to 4 carbon atoms. Preferred alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, and butyl.
The term xe2x80x9calkenylxe2x80x9d as used herein, means an unsubstituted or substituted, straight or branched hydrocarbon chain having at least one olefinic double bond. Said hydrocarbon chain having 2 to 8 carbon atoms, and preferably, unless otherwise stated, 2 to 4 carbon atoms.
The term xe2x80x9calkynylxe2x80x9d as used herein, means an unsubstituted or substituted straight or branched hydrocarbon chain having at least one triple bond.
The term xe2x80x9csubstitutedxe2x80x9d, as used herein, means the replacement of one or more hydrogen radicals in a given structure with a radical selected from a specified group. When more than one hydrogen radical may be replaced with a substituent selected from the same specified group, the substituents may be either the same or different at every position.
The term xe2x80x9cheteroalkylxe2x80x9d, as used herein, means an unsubstituted or substituted, saturated chain having from 3 to 8-members and comprising carbon atoms and one or two hereroatoms.
The term xe2x80x9ccarbocyclic ringxe2x80x9d or xe2x80x9ccarbocyclexe2x80x9d, as used herein, means an unsubstituted or substituted, saturated, unsaturated or aromatic, hydrocarbon ring. Carbocycles may be monocyclic or polycyclic: Monocyclic rings generally contain from 3 to 8 atoms, preferably 5 to 7 atoms. Polycyclic rings containing two rings, contain 6-16, preferably 10 to 12 atoms and those with three rings generally contain 13 to 17, preferably 14 to 15, atoms.
The terms xe2x80x9ccycloalkylxe2x80x9d or xe2x80x9ccycloalkanexe2x80x9d, alone or in combination with any other term, refers to a stable non-aromatic 3-to 8-membered carbon ring radical which is saturated and which may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. The cycloalkyl may be attached at any endocyclic carbon atom which results in a stable structure. Preferred carbocycles have 5 to 6 carbons. Examples of carbocycle radicals include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclohexenyl, indane, tetrahydronaphthalene and the like. Said carbocycles may be substituted or unsubstituted.
The term xe2x80x9cheterocyclic ringxe2x80x9d or xe2x80x9cheterocyclexe2x80x9d, as used herein, means is an unsubstituted or substituted, saturated, unsaturated or aromatic ring comprised of carbon atoms and one or more heteroatoms in the ring. Heterocyclic rings may be monocyclic or polycyclic. Monocyclic rings generally contain from 3 to 8 atoms, preferably 5 to 7 atoms. Polycyclic ring systems consisting of two rings generally contain 6 to 16, preferably from 10 to 12 atoms. Polycyclic ring systems consisting of three rings generally contain 13 to 17 atoms, preferably 14 to 15 atoms. Each heterocyclic ring must have at least one nitrogen atom. Unless otherwise stated the heteroatoms may be independently chosen from nitrogen, sulfur and oxygen.
The term xe2x80x9carylxe2x80x9d, as used herein, means a mono- or bicyclic carbocyclic ring system having one or two aromatic rings including, but not limited to, phenyl, naphthyl, tetrahydronaphthyl, indanyl, indenyl, and the like. Aryl groups (including bicyclic aryl groups) can be unsubstituted or substituted with one, two or three substitutents independently selected from lower alkyl, haloalkyl, alkoxy, amino, alkylamino, dialkylamino, hydroxy, halo, and nitro. In addition, substituted aryl groups include tetrafluorophenyl and pentafluorophenyl.
The term xe2x80x9cheteroarylxe2x80x9d, as used herein, means a mono- or bi-cyclic ring system containing one or two aromatic rings and containing at least one nitrogen, oxygen, or sulfur atom in an aromatic ring. Heteroaryl groups (including bicyclic heteroaryl groups) can be unsubstituted or substituted with one, two or three substituents independently selected from lower alkyl, haloalkyl, alkoxy, amino, alkylamino, dialkylamino, hydroxy, halo and nitro. Examples of heteroaryl groups include but are not limited to pyridine, pyrazine, pyrimidine, pyridazine, pyrazole, triazole, thiazole, isothiazole, benzothiazole, benzoxazole, thiadiazole, oxazole, pyrrole, imidazole and isoxazole.
The term xe2x80x9calkoxyxe2x80x9d, as used herein, means an oxygen atom having a hydrocarbon chain substituent, where the hydrocarbon chain is an alkyl or alkenyl (e.g.,xe2x80x94O-alkyl or xe2x80x94O-alkenyl). Preferred alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, and alkyloxy.
The term xe2x80x9chydroxyalkylxe2x80x9d, as used herein, means a substituted hydrocarbon chain which has a hydroxy substitutent (e.g., xe2x80x94OH), and may have other substituents. Preferred hydroxyalkyl groups include, but are not limited to, hydroxyethyl and hydroxypropyl.
The term xe2x80x9ccarboxyalkylxe2x80x9d, as used herein, means a substituted hydrocarbon chain which has a carboxy substituent (e.g.,xe2x80x94COOH) and may have other substituents. Preferred carboxyalkyl groups include carboxymethyl, carboxyethyl, and their acids and esters.
The term xe2x80x9caminoalkylxe2x80x9d, as used herein, means a hydrocarbon chain (e.g. alkyl) substituted with an amino moiety (e.g., NH-alky-), such as aminomethyl alkyl.
The term xe2x80x9calkylaminoxe2x80x9d, as used herein, means an amino moiety having one or two alkyl substituents (e.g.,xe2x80x94N-alkyl), such as dimethylamino.
The term xe2x80x9calkyliminoxe2x80x9d, as used herein, means an imino moiety having one or two alkyl substituents (e.g., -alkyl-Nxe2x95x90).
The term xe2x80x9carylalkylxe2x80x9d, as used herein, means an alkyl moiety substituted with an aryl group. Preferred arylalkyl groups include benzyl and phenylethyl.
The term xe2x80x9caroylxe2x80x9d, as used herein, means the radical ArCO; wherein Ar is an aromatic group. Representative aroyls are benzoyl and naphthoyl.
The term xe2x80x9carylaminoxe2x80x9d, as used herein, means an amine moiety substituted with an aryl group (e.g., aryl-NHxe2x80x94).
The term xe2x80x9caryloxyxe2x80x9d, as used herein, means an oxygen atom having an aryl substituent (e.g., aryl-Oxe2x80x94).
The term xe2x80x9cacylxe2x80x9d, as used herein, means a carbon to oxygen double bond, e.g., Rxe2x80x94CO. Preferred acyl groups include, but are not limited to, acetyl, propionyl, butanoyl and benzoyl.
The term xe2x80x9cacyloxyxe2x80x9d, as used herein, means an oxygen atom having an acyl substituent (e.g., acyl-Oxe2x80x94); for example, alkyl-C(xe2x95x90O)O.
The term xe2x80x9cacylaminoxe2x80x9d, as used herein, means an amino moiety having an acyl substituent (e.g., acyl-Nxe2x80x94); for example, Rxe2x80x94(Cxe2x95x90O)xe2x80x94NHxe2x80x94.
The term xe2x80x9chaloxe2x80x9d, xe2x80x9chalogen atomxe2x80x9d, as used herein, means a chloro, bromo, fluoro, or iodo atom radical. Chloro, bromo, and fluoro are preferred halogen atoms.
The term xe2x80x9cpharmaceutically-acceptablexe2x80x9d salt, as used herein, means a cationic salt formed at any acidic (e.g., carboxyl group), or an anionic salt formed at any basic (e.g., amino) group. Many such salts known in the art, are described in World Patent Publication 87/05297, Johnston et al., published Sep. 11, 1987. Preferred cationic salts include the alkali-metal salts (such as sodium and potassium), and alkaline earth metal salts (such as magnesium and calcium). Preferred anionic salts include the halides (such as chloride), acetate and phosphate salts.
The term xe2x80x9cpharmaceutical compositionxe2x80x9d, as used herein, means a combination of an effective amount of the azapeptide compound of the present invention or mixtures thereof, and at least one pharmaceutically acceptable excipient.
The phrase xe2x80x9can effective amountxe2x80x9d, as used herein, means a therapeutically effective amount of a compound or composition large enough to modify the symptoms and/or condition to be treated, but small enough to avoid serious side effects (at a reasonable benefit/risk ratio), within the scope of sound medical judgment. The effective amount of active ingredient for use in the pharmaceutical compositions and the methods of the invention herein will vary depending upon the severity of the HCV infection, the duration of the treatment, the nature of concurrent therapy, the particular active ingredient being employed, the particular pharmaceutically-acceptable excipients utilized, and like factors within the knowledge and expertise of the attending physician.
The term xe2x80x9cpharmaceutically-acceptable excipientsxe2x80x9d, as used herein, includes any physiologically inert, pharmacologically inactive material known to one skilled in the art, which is compatible with the physical and chemical characteristics of the particular azapeptide compound active ingredient selected for use. Pharmaceutically-acceptable excipients include, but are not limited to, polymers, resins, plasticizers, fillers, binders, lubricants, glidants, disintegrates, solvents, co-solvents, buffer systems, surfactants, preservatives, sweetening agents, flavoring agents, pharmaceutical grade dyes or pigments, and viscosity agents.
The term xe2x80x9coral dosage formxe2x80x9d, as used herein, means any pharmaceutical composition intended to be systemically administered to an individual by delivering said composition to the gastrointestinal tract of an individual, via the mouth of said individual. For purposes of the present invention, the delivered form can be in the form of a tablet, coated or non-coated; solution; suspension; or a capsule, coated or non-coated.
The term xe2x80x9cinjectionxe2x80x9d, as used herein, means any pharmaceutical composition intended to be systemically administered to a human or other mammal, via delivery of a solution or emulsion containing the active ingredient, by puncturing the skin of said individual, in order to deliver said solution or emulsion to the circulatory system of the individual either by intravenous, intramuscular, intraperitoneal or subcutaneous injection.
The present invention relates to azapeptide compounds represented by the formula: 
wherein:
(a) n 3-7;
(b) R1=a substituted or unsubstituted amino acid or analog thereof;
(c) R2=substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl;
substituted or unsubstituted arylalkyl;
substituted or unsubstituted alkoxycarbonyl or
substituted or unsubstituted aryloxycarbonyl;
(d) R3=xe2x80x94Oxe2x80x94CH(R4)xe2x80x94R5, xe2x80x94Oxe2x80x94R5, or xe2x80x94Sxe2x80x94R5,
wherein R4 is selected from the group consisting of:
H;
halo;
cyano;
substituted or unsubstituted alkyl, and
substituted or unsubstituted alkenyl;
and wherein R5 is selected from the group consisting of
substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted haloalkyl;
substituted or unsubstituted haloalkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl, and
substituted or unsubstituted arylalkyl,
or a pharmaceutically acceptable salt thereof.
The present invention further relates to a method of treating Hepatitis C comprising administering to a patient an effective amount (i.e. a therapeutically effective amount) of a compound having the formula: 
wherein:
(a) n=3-7;
(b) R1=a substituted or unsubstituted amino acid or analog thereof;
(c) R2=a substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl;
substituted or unsubstituted arylalkyl;
substituted or unsubstituted alkoxycarbonyl or
substituted or unsubstituted aryloxycarbonyl;
(d) R3=xe2x80x94Oxe2x80x94CH(R4)xe2x80x94R5, xe2x80x94Oxe2x80x94R5, or xe2x80x94Sxe2x80x94R5,
wherein R4 is selected from the group consisting of:
H;
halo;
cyano;
substituted or unsubstituted alkyl, and
substituted or unsubstituted alkenyl;
and wherein R5 is selected from the group consisting of
substituted or unsubstituted alkyl;
substituted or unsubstituted alkenyl;
substituted or unsubstituted haloalkyl;
substituted or unsubstituted haloalkenyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl;
substituted or unsubstituted heteroaryl, and
substituted or unsubstituted arylalkyl,
or a pharmaceutically acceptable salt thereof.
Preferably, in the formulas shown above, n is 3-7, more preferably n is 4-7 yet most preferred, n is 5.
R1 is a substituted or unsubstituted amino acid or analog thereof. Preferably said amino acid is selected from the group consisting of Alanine (Ala), Arginine (Arg), Asparagine (Asn), Aspartic Acid (Asp), Cysteine (Cys), Glutamic Acid (Glu), Glutamine (Gln), Glycine (Gly), Histidine (His), Isoleucine (Ile), Leucine (Leu), Lysine (Lys), Methionine (Met), Phenylalanine (Phe), Proline (Pro), Serine (Ser), Threonine (Thr), Tryptophan (Trp), Tyrosine (Tyr), Valine (Val) and analogs thereof. Most preferably said amino acid is selected from the group consisting of: Pro, Val, Glu, and analogs thereof. Preferred analogs are substituted proline, pipecolic acid, cyclohexylglycine, tert-butylglycine, D-xcex3-carboxyglutamic acid (D-Gla), and aminoadipic acid.
Preferably R2 is a substituted or unsubstituted alkyl, heteroalkyl, cycloalkyl, aryl, heteroaryl, arylalkyl, alkoxycarbonyl or aryloxycarbonyl. More preferably R2 is a substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl or substituted or unsubstituted cycloalkyl. Most preferred, R2 is a substituted or unsubstituted lower alkyl, e.g. ethyl, n-propyl, n-butyl, allyl, and cyclopropylmethyl or heteroalkyl, e.g. methylsulfanylmethyl, ethylsulfanylmethyl and CN-methyl. Still more preferably R2 is n-propyl or n-butyl.
R3 is xe2x80x94Oxe2x80x94CH(R4)xe2x80x94(R5); xe2x80x94Oxe2x80x94R5 or xe2x80x94Sxe2x80x94R5. Preferably R3 is xe2x80x94Oxe2x80x94CH(R4) (R5), wherein, R4 is selected from the group consisting of:
H;
halogen;
CN, and
alkyl,
and wherein R5 is selected from the group consisting of:
substituted or unsubstituted alkyl;
substituted or unsubstituted haloalkyl, e.g. trichloromethyl;
substituted or unsubstituted heteroalkyl;
substituted or unsubstituted cycloalkyl;
substituted or unsubstituted aryl, (e.g. 2- or 4-nitrophenyl, 4-methoxycarbonylphenyl, 4-fluorophenyl, 4-chlorophenyl, or 4 methylphenyl);
substituted or unsubstituted heteroaryl, and
substituted or unsubstituted arylalkyl.
More preferably, R4 is halogen e.g. bromo, chloro, iodo, or fluoro.
Preferably, R5 is selected from substituted or unsubstituted alkyl, (e.g. methyl, ethyl, n-propyl or n-butyl) or substituted or unsubstituted haloalkyl, (e.g. trifluoromethyl, or trichloromethyl). More preferred, R5 is substituted or unsubstituted haloalkyl, with trichloromethyl being the most preferred.
The following Examples further describe and demonstrate the preferred embodiments within the scope of the claimed invention. The following examples are given solely for the purpose of illustration, and are not to be construed as limitations of the present invention since many variations thereof are possible without departing from the spirit and scope of the invention.